Rate of climb indicator



Oct. 6, 1936. E. HORN 72,056,354

, RATE OF CLIMB INDICATOR Fi-led Sept. '1935 \\\\\'IIIIik\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\- vii-mm Patented Oct. 6, 1936 v UNITED STATES PATENT OFFICE RATE OF CLIMB INDICATOR Erhard Horn, Leipzig, Germany Application September 9, 1935, Serial No. 39,822 S U In Germany September 22, 1934 1 Claim. (C1. 264-1) This invention relates to a device for indicat- The portion of the chamber at one side of the 4 ing the climbing speed and rate of vertical depressure plate I communicates with a port 11, scent of an aircraft. which, as above stated, is in communication with The object of the invention is the provision of the reservoir 0. through the pipe b. At the oppo- 5 a device of this character in which the indicating site side of the pressure plate I, the chamber c is 5 pointer is instantaneously responsive to variain communication with a port e communicating tions in the ascent and descent of aircraft. with the outside air.

According to the invention the measuring The shaft 12 is located at the center of the cirprinciple is based on the measurement of the cular chamber 0 and the pressure plate I is of 4 pressure difference produced during the ascent such dimensions as to provid a clearance 'space 10 and descent of the aircraft, between the outside of about one-tenth millimeters on all sides thereair and the air contained in a vessel in communiof between it and the walls of said chamber. Apcation with the outside air through a small oriproximately the same clearance space is afforded fice. The measurement of this pressure differbetween the shaft 2' and the partition wall I.

15 ence is not, however, effected by means of a dia- When the aircraft ascends, the atmospheric 10 phragm box as in prior'types of rate ofclimb pressure decreases in accordance with the rate indicators, but by means of a pressure plate of climb of the aircraft. The air contained in instrument. w p the reservoir a, therefore, flows outwardly there- In the accompanying drawing wherein an imfrom and since it can only follow the path over proved embodiment of the invention is illusthe clearance space or gap between the wall of tratd; I the chamber c and the pressure plate f, said plate Figure 1 is a frontelevatlon of the indicator is moved against the tension of the spring It to with parts removed. an extent corresponding to the velocity of the air Fig. 2 is a transverse section through the indiwhich, as will be understood, depends upon the cator showing the connection of the latter with prevailing diiference between the air in the reser- 5 an air reservoir. voir and the outside air.

Fig. 3 is a perspective view of the indicator Apressure difierence between the air within the removed from the housing and showing the inreservoir a and the outside air occurs whenever ternal parts thereof. the aircraft ascends or descends and the equal- Referring to the drawing in detail a designates -i ation of t e pressures a y be t d y so an air reservoir of approximately half a liter the passage of air through the space or gap be-' capacity whicnis protected against the influences tween the pressure plate f and the wall of the of changing temperature by the well known douchamber, said gap, according to its shape, conble walled covering. stituting a fiat plate opening, comparable with The reservoir 0 is connected by a pipe I) with a a capillary tube. Since, however, said air gap circular air chamber 0 provided in the body 01 of corresponds to a very wide capillary opening and the indicating device, the open top of the chamalso since the spri 76 1183 no like that Of a her being normally closed byacover cz. diaphragm box, the pointer is adjusted to the A pressure plate 1 rigidly secured to the supmeasuring value much more quickly than in the 40 porting shaft 1'. is located in the air chamber 0 known types of rate of climb indicators employ- 40 and is normally held in a predetermined position ing diaphragm boxes.

by a spring k. I A further advantage of the improved indicator The shaft i is mounted to freely rotate in bearlies in the fact that the mechanism can withstand ings g and It provided respectively in. the body substantially any pressure, that is to say, it has c1 and a bearing arm 0 supported thereby. The an overload capacity as compared with the grade 45 cover or is provided with an opening 1) through of climb indicators having diaphragm boxes.

which the shaft i passes and a pointer 11:. is rig- A further advantage lies in the fact that the idly secured to the shaft i and is movable over pressure plate I and shaft 1' are of small weight the plate 11. having the usual graduated scale and in the consequent ability of these parts to thereon. withstand shocks. J 4 50 n The body or is provided internally, with a I claim: sector-shaped partition wall 1 extending from'the A rate of climb indicator comprising a therannular wall of the chamber 0 into close. relation mally insulated reservoir, a circular chamber, a

to the shaft i, the wall l being disposed oppo stationary partition wall arranged in said cham- 156 Site to the normal Position 01 the'pressul' Plat 1. her, a shaft rotatablymounted in the axis of said chamber, a pressure plate rotatable with said shaft in said chamber, spring means normally retaining said pressure plate in predetermined position, means connecting said chamber at one side of said pressure plate with said reservoir, and means connecting the chamber at the opposite side of said pressure plate with the atmosphere, said pressure plate being arranged to provide a gap between the edges thereof and the walls of said chamber, the dimensions of said gapJ-being such that it serves as a capillary orifice whereby upon occurrence of a pressure difierence between the atmospheric air and the air in said reservoir, the flow of air through said gap causes displacement of the pressure plate and shaft.

ERHARD HORN. 

